Muscles are not always the prime mover.
Sometimes, they got some other stuff they
do. So what is the prime mover? What is the definition of prime mover? I'm glad
that you can read the first sentence up there.
What did you guys know as the prime mover? The idea ... I can write definitions
all day, the idea is that you guys understand it for yourselves. What would
you call the prime mover; you can use your own words, you don't need to use
technical terms...the main thing...
by "main," what do you mean? The muscle that does what?
Okay so the muscle that can produce the most force for that
particular joint action. For the most part that's, that's right.
That's important to think about because it's like how do you
decide which is the prime mover? Well, generally speaking, it's probably going
to be the, if it's the muscle that produces the most force, it's also going to
be the muscle that's the largest, for the most part. it is. It is the muscle that is
largest. Sometimes it's the muscle that has the best angle. You guys get what I'm
saying? That's most well aligned to produce that joint action.
Sometimes the term agonist is used, have you guys ever heard that? The reason I
don't like agonist is because some people use that term as prime mover and
then some people use, "well technically an agonist is anything that will do the
thing you want, right. So it could be all of the muscles that cause flexion like
the graphs that we're doing. Rather than the one that is able to produce the most
force for flexion. (So we should not worry about agonist as a terminology?)
No, you should know it. in the back of your head.
I'm just telling you I'm going to use prime mover so that we are clear. (So prime mover,
single muscle, agonist of course could be lots of muscles) Agonists, if you look, if you
technically think about what agonist means, it could mean all. What I'm telling
you guys is a lot of people will use the term agonist to mean prime mover. A lot of
people use those two synonymously. I don't think the word agonist is very
clear. I'm not going to use it. I'm going to use prime mover. Prime mover - muscle most
responsible or the muscle that produces the most force for the joint
action we're looking at, under load. Synergists. What is synergy? (Working together.)
Working together. So a synergist, you ready for this, is all the muscles
that help the prime mover, or you could think about it this way, they're all the
muscles that produce the joint action we're looking at, that aren't what? The
prime mover. That's it. That's it.
This isn't a memorization thing, remember this whole course is built around you
guys not doing what?
Rote memorization. I want you guys to understand. Antagonists. If I
antagonize you what am I doing?
Yeah, trying to resist you in some way, right? Antagonists are all the muscles
that oppose the prime mover and synergists. Considering this in a, "How are
we going to figure this out?" sort of way, antagonists are going to be all the
muscles to do what? The opposing joint action. Antagonists. You with me? So we got
the prime mover- the muscle that can produce the most force, we got the
synergists- all of the other muscles that produce that joint action, the
antagonists- all of the muscles that produce the opposite joint action.
Now we get tricky.
Neutralizers. A neutralizer- a muscle that opposes the unwanted joint motions is
created by the prime mover and/or synergists and/or muscles that prevent
the ancillary motion, unwanted ancillary motion in a movement.
That doesn't make a whole lot of sense yet right?
Okay, so let me give you an example. If i do hip extension, right, who's my primary
muscle for hip extension? The glute max. The glute max does extension though and
external rotation. But I don't want external rotation.
I don't want to run like this right, like with my feet flipping out.
So how do I prevent the external rotation? I have to have my internal
rotators tone up a little bit so that they keep my legs straight.
That's a neutralizer. It's when a certain joint motion is paired with some
ancillary motion we don't want, we need those other muscles to come in and keep
us in a straight line. For today's class, the only part of that definition we're
going to worry about is the ancillary motion of the prime mover. We're going to
neutralize that. So going back to the...hip
extension example, forget everything else that's going at the hip, today we're
going to say neutralizers are the muscles that will oppose the extra
motion of the prime mover. You guys with me on this?
The extra motion yeah, not the main motion.
Yeah. So, yeah exactly. So if I'm doing hip extension and I want my glute max
it's going to produce extension and external rotation. We're not opposing extension.
That's fine, you're right that would be the antagonists, but that external
rotation, we don't want. And remember, all your glute max knows how to do is fire.
It doesn't know how to separate between extension and external rotation. What's
going to control that is some neutralizers coming in to keep me in a straight line.
Stabilizers. I should warn you with this definition. My definitions
are not going to be the same as the definitions in every textbook, partly
because the definitions in every textbook vary wildly when you get to
these more complicated terms. Also partly because I like to teach in a conceptual
way. I want you guys to be able to figure this stuff out for yourselves.
I've had to either scale down or modify definitions to make sure that they stay
clear and conceptual and separate from each other.
Stabilizers, in my book, are muscles that basically, more or less, control that
arthrokinematic motion. They're muscles that are closer to the joint whose main
purpose is that stabilization function. But the proximal stabilization function
of a joint. So who are my stabilizers always going to be for any shoulder
motion? Rotator cuff. You guys get me there?
Fixators. Fixators are muscles that help lock down the proximal joint, not the one
we're working, but the other one. You guys get what I'm saying?
Lock that one down so that I only get motion and force production where I
intended. Easy example for you guys, if I'm doing hip extension, what joints need
to be locked down?
Sure, you could be right, too, if I was doing something like a deadlift, sure, I
might need to stabilize my knee.
You're not wrong, but you guys get what I'm saying there? So if I need to work
I need to fixate this. Who would my stabilizers for my hip be? Deep rotators.
Remember that? Remember those deep, deep, deep muscles.
In a wider definition of, this is where... so that's a great it's a
great example guys, that's a great example of where definitions have a
tendency to do this. I said this is a fixator, the deep rotators of the hip are
stabilizers for the hip and then I said "What stabilizes?" and he said "Glute medius."
And yesterday I said that the glute medius was the primary frontal plane
stabilization mechanism of the pelvis.
Yes, they're both correct. The gluteus medius has a very important
stabilization function as many muscles do. When you're breaking down stuff for
this, for specific joint actions, stabilizers are the muscles that do what?
Just work on those very small motions that keep the joint moving the way it's
You guys with me? Not that the gluteus medius doesn't help stabilize the pelvis in a
larger, more global picture of what we're looking at. So easy to confuse fixator
and stabilizer that I guarantee those two terms will never be defined the same
way in two text books. (Are fixators usually like small, refined muscle) No, no. If I was working my
what would I need to fixate to be able to move my arm well? My scapula. So all
of the muscles of my scapula become fixators. The stabilizer would be at the
shoulder which would be my? My rotator cuff. You guys kind of seeing how this is
going. All you're doing is is starting to understand how everything works
together. I'm not saying you won't find other definitions in other textbooks but for
the assignment we're about to do, I think you'll find these definitions useful.
All right so let's do shoulder horizontal adduction.
Let's see if we can figure this out. You want to do the first one together.
No I will not think for you. Well look, if you want to pay me my salary to
follow you around and help you with your clients, we can work something out.
Or I could just take your test for you? I think that's cheating.
I think there's a problem with that academically, but I could be wrong. If you
find out that I'm wrong, you let me know. Okay. Get back to me.
So let's do shoulder horizontal adduction, what movement are we
talking about? So what, what exercise am I talking about? Benchpress, flyes
pushups, you guys can think whatever you want we're doing shoulder.
We're just looking here though, not here, just here, in a bench press.
Cool, all right. Prime mover - almost wrote agonist. Spent so much time talking about
agonist, almost wrote it down.
Actually that's not gonna work, let's do this.
Prime mover, who's the prime mover? Pectoralis major.
Synergists. (Anterior delt) Antagonists. There could be if there was more than one, it's not for this case.
Right. You're going to see in some of our other graphs, there's a lot of muscles
per category. Posterior delt. There's a reason I picked this graph to start with.
Some of these graphs get very complicated.
Who's next? Neutralizers. Neutralizers so we got to go back up to pec major and
think, "all right,
my pectoralis major does more than just horizontal adduction, what else does it
want to do? Probably internally rotate. It actually does a few things, but we'll
stick with internal rotation because that's a big one. The last thing I want to do
is take up a heavy bench press and internally rotate. I'm guessing that's
dangerous, guessing that's a dangerous thing to do.
So who would I used to neutralize internal rotation? Which ones? Specific.
The external rotators. So it externally rotates very nice, it is
infraspinatus, teres minor
One more. Muscles can be in two different categories. Posterior delt.
Stabilizers. What stabilizers for the shoulder? Would be rotator cuff.
Yes so would be ... I'm just going to write down infraspinatus and teres
minor since we already went there. Who are the other two? Subscapularis and
Fixators. Who my fixators? Muscles that's that stabilize the scapula. I have five
muscles that cross my axial-scapular joint, you guys remember what they were?
Rhomboids, trapezius, levator scapulae
...no, just muscles that move the scapulae, you remember? You guys have
totally forgotten your protractors. Pec minor...and...thank you.
Serratus anterior. Serratus anterior may be the most important stabilizer of
the scapula. Kind of interesting to think that all that's working during shoulder
How'd you guys do? Horrible. (laughs)
All right that's what we just did. All right, scapular protraction. Hit it!
I got to go back into superstar status, we got to get this next one up right you, guys ready?
All right I can go on rants for forever about stuff but we have to get this done.
This was a little tougher, right? Scapular protraction leads to a lot of really
confusing little relationships, but if you put a little thought into it,
you'll figure it out. Scapular protraction. Who is my primary scapular protractor?
Serratus anterior. Yeah, that one's a little stronger. Serratus, I think. Honestly guys
I'm not really worried about your... the way you say it. I'll correct you if I think
something will get you embarrassed in your clinic. I would never correct you.
Neutral... if you said neutralizers I'd have to go ahead and, and say something
that sounds a little bit like neutral lizard and I don't know what a neutral
lizard is. Synergists. Pec minor. Remember we're talking about
protraction, so these muscles have to cross from axial, the ribcage, to the
scapula, or the spine of the scapula. Antagonists are going to be all the
muscles that do what? Retraction.
So what are retractors? Rhomboids, mid-traps.
Neutralizers. Well, what are we trying to neutralize the radius anterior does...
protraction and upward rotation. That's a good one too,
it does, you're not you're not wrong, it does posterior tipping, so we could say
we need to neutralize posterior tipping. But we're going to say neutralize the
upward rotation force which means I need to find all the...all the muscles
that do downward rotation. What is downward rotators? Levator scapulae,
Man, evidently I didn't teach this muscle very well yesterday, pectoralis minor.
Stabilizers. This is a tough one with this one. This is a really tough one.
Yeah, I mean there's a lot of ways to think about this one. Serratus
anterior is actually probably considered the primary stabilizer for your... for your
scapula but it's also our prime mover. If you didn't put anything down.
that's okay. If you want to say lower traps you want to say serratus anterior, I
wouldn't be mad at you either, because those two muscles are almost always
under active individuals and usually need a little bit of work. So we can, we
can say that serratus anterior. Oh you're not being given charity don't worry
about it. (student speaking) Depends on what we're talking about, right?
What if we were talking about external rotation of the shoulder? Would your
stabilizers become your prime movers? Fixators, what am I trying to fixate?
(Wouldn't levator be a stabilizer?) It could be it could be, it
honestly, this term doesn't work real well for this graph and that
happens. It's okay. This is a mental exercise, the fact that it's getting you
thinking is good. Fixators. What is going to need to be stable and functioning well
for your scapula to move well. Your spine and trunk.
Usually we move proximally, okay, yeah.
In order for your scapulae to move well, all this has to be nice, right, it has to be a
nice cylinder. So now all of our fixators are what? All our core muscles. Should we
try to list them all? Well yeah I mean we could say that too, you're right,
depending on what motion we're talking about, it could go all the way down to my
toes, but let's start with core. Let's just start with the trunk muscles, right.
So we said transverse abdominis and with your transverse abdominis we could talk
about something called your intrinsic stabilization subsystem. Stay with me
here, guys. You're ISS, all right so your intrinsic stabilization subsystem.
Your intrinsic stabilization subsystem is made up of your TVA, multifidus,
diaphragm and pelvic floor. We then can add the more superficial movers on top of
that right. Which are going to be my rectus abdominis, let's say obliques,
since we know both are included.
Starts with an E... erector spinae Starts with a Q... quadratus lumborum
It is deep, but it's still part of our core so it's, and it's one of the bigger
movers. How did we do? Am I missing anything?
I think we're okay. I just wrote obliques -internal and external. Good.
Oh I guess we could throw the lats up there, but that's going to get a little
tricky because the lats also connect into the shoulder and how does it affect
the scapula? Guys these are the... this is what I'm setting you up for, is
the never-ending mental game that you can play with yourself.
All right so let's go ahead into hip extension.
All right, guys let's do hip extension. Gluteus maximus, done. All right, hip
extension prime mover - glute max. Everybody's favorite muscle, now let's go
for the synergists though. Biceps femoris, the long head, good. Getting a little bit
more specific, right. The short head only goes up to about halfway up on the femur.
Doesn't actually cross the hip.
What else? So biceps femoris long head semi's and
posterior adductor magnus. There is no such thing as abductors for
muscles. There are muscles that abduct, there are adductors.
Just realize if you do you're just referring to several muscles. Antagonists.
Who are my antagonists? All the muscles that do hip flexion so iliacus, psoas... psoas,
rectus femoris. Keep going.
Gluteus minimus, nice. (Sartorius) Nice.
PBLMG anterior adductors, right? Pectineus, brevis, longus, magnus
gracilis. Anterior adductor magnus on that one. Neutralizers. What are we trying to
neutralize? So we're trying to do,
we're trying to get some internal rotation activity because my glute max
wants to do extension and external rotation.
All right so who are my internal rotators? TFL, definitely. The glute min,
and...anterior fibers of glute medius, if you want to write it down.
Although we've also talked about how the posterior fibers of gluteus medius
externally rotate and are usually ones that become under active and the
ones that I was talking about yesterday that we need to work, work, work, work, work.
TFL, glute min. (Student question. Those are which type of rotators.) All of my adductors. We're
We already have it up there too.
It's up there in a different category, it's going to be in this category too.
Nice job. Semi's. Stabilizers. Already kind of mentioned this, these are the ones
that are close to the joint who are going to help us keep, yeah, the deep rotators of
the hip. (Student question) They are, but they're also, they're stabilizers of the hip. Fixators.
Who do we need to fixate? (Oppostite hip) That's an interesting idea.
So if I needed to kick a ball, would I have to fixate the side? Potentially.
Potentially. If I'm just walking though, who needs to stay pretty stable or if
I'm running. Core. Should we write down all of them again. I'll let you get away
with core this time.
Okay, let's do it. Okay, you said it.
All right so, let's go. Intrinsic stabilization subsystem what are those guys?
TVA, multifidus, diaphragm,
pelvic floor. Keep going. Now we're onto our global stabilizers - obliques.
Okay, keep going. Rectus abdominis, keep going.
Erector spinae, keep going. One more. QL. Nice job, guys. That was quick too.
All right, I think we got one more joint action. Hip abduction, let's hit it, and
then you guys will be back to me talking for a little while until we get to lunch.
Which movement am I looking at? Abduction. Okay, good. Prime mover? Gluteus medius,
for sure. Synergists. Gluteus minimus and TFL.
Antagonists. Adductors, nice job. That was kind of easy on this one. Adductors,
What's my acronym for adductors? And since this is the last, since this is the last
one "Peanut Butter Leaves Me Greasy" this is the last time we're going to write
the adductors up on the board,
I think for this two-day workshop,
let's break them out. So what are all my adductors, ready? Pectineus, that's the "P."
Peanut butter... brevis. Leaves...longus. peanut butter leaves... longus. Peanut butter
leaves me....magnus. Greasy, peanut butter leaves me greasy... gracilis. And then we
can put post adductor here, since for most of the weekend we've been considering
"Peanut Butter Leaves Me Greasy' as the anterior adductors and kind of the
posterior head of the adductor magnus separately. Neutralizers. (Student question)
Yep, this is definitely one of those graphs where one of our terms starts
looking a little funny right.
Yeah because we have posterior and anterior fibers of the gluteus medius, I
mentioned that a couple times, some internally rotate, some externally rotate.
We do have two internal rotators as synergists, right. So the TfL and the
gluteus minimus are both synergists and both strong internal rotators for the
hip. Usually what happens is we get internally rotated bias, right. People
tend to do this, that knees cave-in and internally rotate. So if I'm just
going to kind of think through logically, maybe a little beyond this assignment, we
look at neutralizers and we go,
"Why, what way am I neutralizing?" and then I would think to myself, well with this
much of a bias towards internal rotation, I might go, "I need more external rotation
force." Right so we could do glute max, biceps femoris, TFL is an internal
rotator. What about my piriformis and the deep rotators right?
Oh haha, nice job. Psoas and iliacus too. Both external rotators of the hip. Could even
put down adductor magnus, if you really wanted to.
Yeah nice job. Nice job thinking through that.
Stabilizers. Yes, so this is going to be deep rotators of the hip again and then what my fixators
going to be? Your core, just like the last graph we did. Yeah, so all I did is
the intrinsic stabilization subsystem is those intrinsic muscles that have more
of a role in stabilization than they do in movement and then all of the other
muscles that cross the lumbar spine. Which are, we could look at as global
movers or global stabilizers of the trunk.
Nice job guys.
You did a good job with this, these activities. These graphs aren't easy. Now
if you like doing these graphs, your 20 minutes a day, I wrote down one of these
graphs for every joint action for every major joint and it's up on the website.
I'm talking all of the joint actions for the shoulder, the elbow, the scapula, the
hip, the knee and ankle. It's under kinesiology. It says kinesiology of the
hip, kinesiology of the ankle, kinesiology the shoulder. B2C fitness is the old name